Power transmission



Sept. 30, 1958 M CKELLAR K. GRAHAM ETAL 2,853,951

POWER TRANSMISSION Filed April 1, 1957 FIG.!

45 0 44 58 INVENTORS MAC KELLAR K. GRAHAM 54 ROBERT W. BREHM 38 46 36' BY FIG. 3

' ATTORNEYS United rowan TRANSMISSION Application April 1, 1957, Serial No. 649,713 2 Claims. (Cl. 103l36) This invention relates to power transmissions, and is particularly applicable to those of the type comprising two or more fluid pressure energy translating devices, one of which may function as a pump and another as a fluid motor.

The invention is more particularly concerned with a vane pump or motor construction adapted for use in hydraulic power transmission systems.

A form of pump or motor in common use in the hydraulic power transmission field utilizes a housing containing a cam ring member of elliptically shaped contour which serves as a vane track. Within the cam ring is mounted a rotor having a plurality of substantially radial vane slots, each slot having a vane slidable therein. The outer ends of the vanes are maintained in contact with the vane track, which thereby controls the inward and outward movements of the vanes as the rotor turns. The rotor and vane track form small working chambers between each pair of adjacent vanes, which undergo alternate expansion and contraction due to the outward and inward movements of the vanes induced by the vane track.

An essential condition to efficient operation of this type of device is the maintenance of the outer ends of the vanes in contact with the vane track. This is a particular problem during starting, when the device is used as a motor. Also, when the vanes pass through the high pressure zones during operation as either a pump or motor, there may be a tendency for the vanes to separate from the vane track due to the high pressure on their outer ends. Some means in addition to centrifugal force is necessary to maintain the outer ends of the vanes in contact with the vane track. One prior art method of assuring this contact has been the connection of the high pressure side of the device to the undersides of the vanes. It has been found necessary to supplement this high pressure in some instances by the use of springs.

One of the prior art approaches to this problem has been the provision of coil springs to bias each vane outward into contact with the vane track. It has been found that the high frequency compression and expansion cycle of these necessarily small springs during operation of the device causes them to fatigue rapidly.

Another prior art solution to this vane biasing problem was through the use of hell crank levers as illustrated in the patents to Klessig, No. 2,641,193, and to Jones, et al., No. 2,641,194. Although functionally excellent, these units are somewhat costly since the levers are intricately shaped and require a plurality of bushings mounted on pivot pins in the rotor.

It is therefore an object of this invention to provide in devices of this type an improved means of preloading the vanes into contact with the vane track.

It is another object of this invention to provide preloading of the vanes into contact with the vane track by utilizing spring levers which are not subject to the fatigue of coil springs and which eliminate the lever mounting pivot pins in the rotor required in the Klessig and Jones, et a1. devices.

Patent It is still another object of this invention to provide a low cost means for preloading the vanes into contact with the vane track.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred form of the present invention is clearly shown.

In the drawing:

Figure 1 is a sectional view of a vane type pump or motor taken on line 1-1 of Figure 2.

Figure 2 is a sectional view taken on line 2-2 of Figure 1.

Figure 3 is an enlarged view of a portion of Figure 2.

Figure 4 is a sectional view taken on line 44 of Figure 3.

Referring now to Figure 1, there is shown a vane type pump or motor generally designated 10. This device comprises a body member 12, a ring 14 and a head member 16, arranged in a sandwich relation, and secured together by bolts 18 extending through head 16 and ring 14 into threaded holes in body 12. An external connection port 20 registers with passage 22 which leads to pressure chamber 24. Within pressure chamber 24 is fioatably mounted a pressure plate 26, whose plane face 28 is biased rightwardly into contact with plane face 30 of ring 14 by spring 32. Arranged within elliptically shaped vane track 34 of ring 14 and supported on shaft 36 is a rotor 38 having a plurality of substantially radial vane slots 40 each carrying a slidable vane 42. Shaft 36 is spline connected at 46 to rotor 38, and is supported in body 12 by bearings 48 and 50 and is sealed against leakage at its point of emergence from body 12 by conventional shaft seal 52.

A plurality of spring levers 44 are located in each of two grooves 54 in the rotor 38. Spring levers 44 are formed so that a short portion of each end is bent at an angle to the main part of the lever. These short bent portions 45 of the levers 44 rest in notches 56 at the bottom of both sides of vanes 42. A hub portion 58 forms the inner edge of each groove 54. The diam eter of hub 58 is so chosen as to induce deflection of the levers 44 as they span the distance between the two vanes contracted thereby. The degree of deflection is such as to produce the desired outward force on the vanes contacted. Those vanes contacted by any particular one of the spring levers 44 are termed complementary vanes. They are complementary in the sense that they simultaneously partake of movements that are substantially equal and opposite. That is, when one of a pair of complementary vanes is moving inward, the other is moving outward. In the device illustrated, the complementary pairs of vanes are located apart.

Spring levers 44 are placed in grooves 54 in a staggered arrangement in two axially offset planes on each side of the rotor 38 with their bent end portions 45 placed in vane notches 56 of complementary vanes.

Hubs 58 provide low cost support and positioning for the inexpensive spring levers 44. This construction eliminates the costly pins and bell cranks of the heretofore mentioned Klessig and Jones, et a1. patents. The combination of having bent ends 45 and being centrally bowed over rotor hubs 58 of rotor 38 causes spring levers 44 to be stable as regards both axial movement and twist.

The device illustrated is of the balanced, rotary, doublethrow type and each vane will partake of two, cyclic in and out movements for each revolution of the rotor. The rotor is provided with 12 slots and 12 vanes and, as heretofore noted, the complementary vanes will be 90 apart. The motion of each vane on an inward stroke will be transferred to its complementary vane on an outward 3 stroke by the rocking action of the spring levers 44 on the rotor hub 58.

Pressure plate 26 is pierced by two arcuate ports 60 and 62 which are diametrically opposite one another and provide a fluid access path from pressure chamber 24 to the working spaces between the vanes 42. Ports 60 and 62 are indicated by use of hidden'edge lines in Figure 2 to illustrate positional relationship only. A plurality of holes 64 connect pressure chamber 24- with rotor grooves 54 and thereby supply pressure to the underside of the vanes. The working spaces between the vanes are connected on the right, as viewed in Figure 1, with a pair of arcuate ports 66 and 68 diametrically opposite one another and which lead to chamber 70 and to external connection port 72.

In operation as a fluid motor, high pressure fluid will enter pressure chamber 24 via external connection port 20 and passage 22. The high pressure fluid passes through ports 64) and 62 and fills the spaces between vanes 42 causing rotor 38 to revolve and impart a driving force to shaft 367 As rotor 38 revolves, the spaces between vanes 42 will become volumetrically larger due to the extension of vanes 42 in their vane slots 40 as the outer vane ends follow the elliptical vane track 34. As the spaces between vanes 42 volumetrically increase in passing ports 60 and 62, so will they decrease in passing ports 66 and68, due to inward movement of vanes 42 in slots 40. The contraction of the vane spaces at ports 66 and 68 will cause fluid to be, ejected through them into chamber 70 from where it will be drained off by external connection port 72.

It should be noted that the spring levers perform two functions. They serve to preload the vanes into contact with the vane track, and in addition they cause the inward motion of the vanes to be transferred to complementary vanes on a corresponding outward stroke. Performing without substantial change in deflection the levers are therefore not subject to the short fatigue life of the individual coil spring construction. There is thus provided a low cost, efiicient and long lasting vane pump or motor.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. In a fluid pressure energy translating device of the rotary, vane type having a housing including a rotor chamber with a non-circular inner contour forming a vane track, a rotor mounted in said chamber, said rotor having a plurality of generally radial vane slots, 21 vane slidably mounted in each of said vane slots, the outer ends of said vanes contacting said vane track, said vane track causing cyclic in and out strokes of said vanes during a rotor revolution, each inward moving vane having a complementary vane moving outward, that improvement comprising; a hub on said rotor; a groove in said rotor into which the inner ends of the vanes extend; notches in the inner ends of said vanes which register with said groove in said rotor; and a plurality of spring lever members extending between said notches in pairs of complementary vanes, said spring lever members having bent end portions engaging said notches in vanes, each spring lever member having its central portion in biased contact with said rotor hub, thereby resiliently loading a pair of complementary vanes into engagement with said vane track, and transferring motion therebetween by rocking action on said hub.

2. In a fluid pressure energy translating device of the rotary, vane type having a housing including a rotor chamber with a non-circular inner contour forming a vane track, a rotor mounted in said chamber, said rotor having a plurality of generally radial vane slots, a vane slidably mounted in each of said vane slots, the outer ends of said vanes contacting said vane track, said vane track causing cyclic in and out strokes of said vanes during a rotor revolution, each inward moving vane having a complementary vane moving outward, that improvement comprising: a hub on said rotor; a groove in said rotor into which the inner ends of the vanes extend; notches in the inner ends of said vanes which register with said groove in said rotor; and a plurality of spring lever members extending between said notches in pairs of complementary vanes, said spring lever members having bent end portions engaging said notches in vanes, each spring lever member having its central portion in biased contact with said rotor hub, said spring lever members being in two axially offset planes in said rotor groove to avoid interference between adjacent spring lever members as they service their particular pair of complementary vanes, thereby resiliently loading a pair of complementary vanes into engagement with said vane track, and transfering motion therebetween by rocking action on said hub.

References Cited in the file of this patent FOREIGN PATENTS 365,329 France June 22, 1906 

